Smallest QR code size: printer, decoder and phone limits

For print you cannot test, plan on at least 2 cm (0.8 in). Real phones can do better: in our test, an iPhone and an Android phone both read 10 mm codes, even a full contact card, from about 20 cm on a screen. Here are the printer, decoder and phone limits with their numbers.

Published 28 October 2026

The three limits

Limit	Set by	Example
Phone users	Scanning distance	2 cm × 2 cm, which Bitly gives as readable by “most QR Code scanners”; about a tenth of the distance beyond that
Printing	The smallest module a printer draws cleanly	0.254 mm per module at 400 dpi (DENSO WAVE): a version 3 code is 9.4 mm with its quiet zone
Decoding	Pixels per module in the image	A short link decoded reliably from 1.75 pixels per module in a sharp image, 3 in a blurred one (test below)

Size is really module size

A QR code is a grid of square modules. Version 1 has 21 × 21 and every version adds 4 per side, up to 177 × 177 at version 40 (DENSO WAVE). The generator shows the version under every preview; a web address such as https://qrmeadow.com is 20 bytes and becomes version 2, 25 × 25 modules:

At the same printed width, more modules means smaller ones. A 61-module contact card printed 2 cm wide has modules of 20 ÷ 61 = 0.33 mm; a 25-module link at 2 cm has 0.8 mm modules, about 2.4 times wider.

The printing limit

DENSO WAVE’s worked example prints 4 dots per module on a 400 dpi printer: 25.4 ÷ 400 × 4 = 0.254 mm per module, so a version 3 code is 29 × 0.254 = 7.366 mm, or 9.398 mm with the four-module margin on both sides. The same arithmetic for other versions:

Version	Modules	Code at 0.254 mm/module	With quiet zone
2	25	6.4 mm	8.4 mm
3	29	7.4 mm	9.4 mm
11	61	15.5 mm	17.5 mm

These are sizes for a scanner held against a label, not for a phone at arm’s length.

Smaller than a QR code: Micro QR and rMQR

When even version 1 is too big, DENSO WAVE has two related symbologies:

	Micro QR Code	rMQR Code
Shape and size	Square, 11 × 11 (M1) to 17 × 17 modules (M4)	Rectangular, from 7 × 43 to 17 × 139 modules
Finder patterns	One	“One and a half”
Quiet zone	2 modules	—
Capacity	Up to 35 digits (M4); M4 holds less than version 1 of QR Code	12 digits to about 361 characters
Standard	JIS X 0510, November 2004	ISO approval in May 2022

Both are meant for narrow spaces such as parts and thin workpieces. QR Meadow makes standard QR Code only; before using either, check that the scanners or apps your readers use support it.

How few pixels a decoder needs

The same codes were shrunk step by step and read back, sharp and with two levels of blur, at ten random sub-pixel offsets per step:

Content	Version · modules	Sharp: reliable from	Slight blur	More blur
Short link (20 bytes)	2 · 25	1.75 px/module	2.5	3
Wi-Fi network (40 bytes)	3 · 29	1.75	2.5	3
Contact card (233 bytes)	11 · 61	3.25	4.25	4.25
Long tracking link (241 bytes)	11 · 61	3.25	3.25	3.25

Test: codes averaged down in steps of 0.25 px per module, sharp, with one and with two 3 × 3 box blurs; reliable = at least 9 of 10 random offsets decode at that step and every larger one. Decoder jsQR 1.4.0 on synthetic images, not phone photos; how the tests work.

For this decoder, the larger version also needed more pixels per module. Under the stronger blur, the contact card needed 61 × 4.25 ≈ 259 pixels across its modules against 25 × 3 = 75 for the short link: about 3.5 times as many, from the same kind of image.

What a separate camera-model test adds

Rebuilt version 11 grid with padded test text; 36 synthetic inputs per sample and decoder

Rebuilt sample	Apple Vision	ZXing-C++
A11: 10 mm symbol	1/36	1/36
A13: 20 mm symbol	22/36	23/36
A15: 30 mm symbol	33/36	30/36

The rebuilt 10 mm, 61-module sample was much harder to read in the projection model than its clean 300 dpi source. It is the same grid density as version 11 contact data, but this test encoded a label, not an actual vCard, and does not validate adding a contact to a phone. The earlier screen session and this uncalibrated model are different evidence; neither replaces a proof of the finished print.

Separate synthetic-image study, QM-LAB-20261028, not a phone or physical-print test. Distances are projections under assumed camera settings, not measured scan ranges. Method, limits and downloadable results.

What real phones read

With an iPhone and an Android phone, each with its built-in camera app, scanning a computer screen from about 20 cm, every size in the table below was read, by both phones:

Content	10 mm	15 mm	20 mm	25 mm	30 mm
Short link, version 2	read	read	read	read	read
Short contact card, version 8	read	read	read	read	read
Full contact card, version 11	read	read	read	read	read

Phone test: code widths without the quiet zone. One session, one distance, codes shown on a screen rather than printed; details.

So current phone cameras handled codes well below the 2 cm guideline, even a 61-module contact card at 10 mm, where each module is about 0.16 mm (10 ÷ 61). The decoder test fits that picture: from a clean image, a decoder needed only about 3 to 4.25 pixels per module, even for the contact card.

Why 2 cm is still the safe answer for print

The phone test used a sharp, backlit screen at one distance. A print adds ink spread, paper texture, glare and dim light, and people do not always hold the phone steady at 20 cm. The common guidance builds in that margin: the size calculator applies the larger of a tenth of the scanning distance (Bitly) and 1/250 of the distance per module (worked out from QRStuff’s 2011 table, which assumes a 3–4 megapixel camera, so a conservative figure), never under 2 cm. Design to it when you cannot test the final print, and treat smaller codes as possible but something to proof first:

Making a code smaller

• Shorten the content. A short link is version 2; the same destination with tracking parameters can be version 11.
• Leave error correction at M and leave out the logo. A logo forces level H in the generator, which adds modules.
• Keep the quiet zone (why) and print from the SVG or PDF download, so module edges stay sharp.

Questions

Sources

1. Bitly, “What’s the Minimum Size for a QR Code?”
2. DENSO WAVE, “Point for determining the code area” (quiet zone and module size)
3. DENSO WAVE, “Information capacity and versions of QR Code”
4. DENSO WAVE, “Micro QR Code”
5. DENSO WAVE, “rMQR Code”
6. QRStuff, “QR Code Minimum Size” (module size table)
7. jsQR, the decoder used in the tests (GitHub)

Tools used in this guide

• Free QR Code Generator
• QR Code Size Guide: How Big to Print a QR Code

More guides

• Smallest QR code size: printer, decoder and phone limitsHow small can a QR code be? 2 cm for phones, 8.4 mm at 400 dpi, Micro QR and rMQR for tiny spaces, and a decoder test of how few pixels per module work.
• Maximum QR code size: version 40, 2,953 bytes, and how big to print itThe largest QR code is version 40: 177 × 177 modules, 2,953 bytes at level L. Capacity by level, print sizes, and how large versions fared in a decoder test.
• The QR code quiet zone: why four modules, and what happens with lessQR codes need a 4-module quiet zone. What that is in millimetres, where designs lose it, and phone and decoder tests of 0 to 4 modules on busy backgrounds.
• QR code sticker size: square, round and pre-cut labelsHow big a QR code sticker should be: code width and scan range for 1 to 4 inch square and round stickers, and how to fit codes on pre-cut labels.
• QR code size on a business card: what fits, what scansA QR code on a business card: the rules of thumb, card safe zones, and a phone test where a full vCard read at 10 mm from 20 cm.
• QR code size in pixels: exports, screens and the scaling trapHow many pixels a QR code needs: a 1024 px PNG gives a short link 31 px per module. Print resolution maths, screens, and why scaling by odd factors hurts.
• How to print QR code stickers and labels in bulkTurn a CSV into up to 500 labelled QR code stickers: styles that still scan, a label sheet or pre-cut labels, and print settings that keep the size right.
• Do QR codes expire? Static vs dynamic codes, and what the providers’ own rules sayStatic QR codes never expire; dynamic ones can stop. What five providers say happens at trial end, downgrade, cancellation or expiry, and how to choose.